Hunger isn’t in your stomach or your blood-sugar levels. It’s in your mind – and that’s where we need to shape up
I decided to
take a try at the great problem of our time: how to lose weight without
any effort. So I did an experiment on myself. I was ripe for it, if
truth be told. Here I am eight months later and 50 pounds lighter, so
something must have worked. My approach to the problem was different
from the usual perspective. I’m a psychologist, not a doctor. From the
start I suspected that weight regulation was a matter of psychology, not
physiology.
If
weight were a matter of calories in and calories out, we’d all be the
weight we choose. Everyone’s gotten the memo. We all know the ‘eat less’
principle. Losing weight should be as easy as choosing a shirt colour.
And yet, somehow it isn’t, and the United States grows heavier. It’s
time to consider the problem through an alternative lens.
Whatever else it is, hunger is a motivated state of mind.
Psychologists have been studying such states for at least a century. We
all feel hungry before dinner and full after a banquet, but those
moments are the tip of the iceberg. Hunger is a process that’s always
present, always running in the background, only occasionally rising into
consciousness. It’s more like a mood. When it slowly rises or eases
back down, even when it’s beneath consciousness, it alters our
decisions. It warps our priorities and our emotional investment in
long-term goals. It even changes our sensory perceptions – often quite
profoundly.
You
sit down to dinner and say: ‘That tiny, little hamburger? Why do they
have to make them so small? I’ll have to eat three just to break even.’
That’s the hunger mood making food look smaller. If you’re full, the
exact same hamburger looks enormous. It isn’t just the food itself. Your
own body image is warped. When the hunger mood rises, you feel a little
thinner, the diet feels like it’s working and you can afford a
self-indulgence. When satiety kicks in, you feel like a whale.
Even
memory can be warped. Suppose you keep a log of everything you eat. Is
that log trustworthy? Not only have you drastically misjudged the size
of your meals, but you’ve almost certainly forgotten items. Depending on
your hunger state, you might snarf up three pieces of bread and after
the meal sincerely remember only one. One recent study
found that most of the calories people eat come through snacks between
meals. But when you ask people, they deny it. They’re surprised to find
out just how much they snack.
The
hunger mood is hard to control, precisely because it operates outside
of consciousness. This might be why obesity is such an intractable
problem.
The
hunger mood is controlled by the brain stem. The part most responsible
for regulating hunger and other basic motivated states is called the
hypothalamus, and it sits at the bottom of your brain. It has sensors
that literally taste the blood. They detect levels of fat, protein and
glucose, as well as blood pressure and temperature. The hypothalamus
gathers this data and combines it with sensory signals that percolate in
through other systems in the brain – fullness in the gut, the feel and
taste and smell of food, the sight of food, even the time of day and
other surrounding circumstances.
Given
all this data, the neural circuits train up on our dietary habits.
That’s why we get hungry at certain times of the day – not because of an
empty stomach, but because of a sophisticated neural processor that
anticipates the need for more nutrition. If you skip a meal, at first
you feel acutely hungry, but then you actually begin to feel less hungry
again as that accustomed mealtime passes by. That’s also why we get
full at the end of a meal. Again, not because of a full stomach. If
that’s your only signal, then you’re drastically overeating. As
counterintuitive as it might sound, there’s normally a healthy gap
between feeling full and having your stomach actually
full. Psychological fullness is a feeling of sufficiency that comes from
a much more complex computation. The hypothalamus in effect says:
‘You’ve just eaten a burger. I know from past experience with burgers
that in about two hours the protein and fat in your blood will rise.
Therefore, in anticipation, I’ll turn off your hunger now.’ The system
learns, anticipates, and regulates. It operates in the background. We
can consciously interfere with it, but not usually to good effect.
Take in fewer calories and you’ll lose weight. But explicitly try to reduce calories, and you’ll do the exact opposite
Here’s
what happens when you interfere with your hypothalamus – when medical
advice collides with psychology. Let’s say you decide to cut back on
calories. You eat less for a day. The result? It’s like picking up a
stick and poking a tiger. Your hunger mood rises and for the next five
days you’re eating bigger meals and more snacks, perhaps only vaguely
realising it. People tend to judge how much they’ve eaten partly by how
full they feel afterward. But since that feeling of fullness is partly
psychological, if your hunger mood is up, you might eat more than usual,
feel less full than usual, and so mistakenly think that you’ve cut
back. You might feel like you’re making progress. After all, you’re
constantly vigilant. Sure, now and then you slip up, but you get
yourself right back on track again. You feel good about yourself until
you get on a scale and notice that your weight isn’t responding. It
might go down one day and then blip up the next two days. Dancing under
the surface of consciousness, your hunger mood is warping your
perceptions and choices.
I’m not denying the physics here. If you take in fewer calories, you’ll lose weight. But if you explicitly try
to reduce calories, you’re likely to do the exact opposite. Almost
everyone who tries to diet goes through that battle of the bulge. Diets
cause the psychological struggle that causes weight gain.
Let’s
say you try another standard piece of advice: exercise. If you burn
calories at the gym you’ll definitely lose weight, right? Isn’t that
just physics? Except that, after you work out, for the rest of the day
you’re so spent that you might actually burn fewer calories on a gym day
than on a regular one. Not only that, but after a workout you’ve
assuaged your guilt. Your emotional investment in the cause relaxes. You
treat yourself to a chocolate chip muffin. You might try to be good and
decline the muffin, but the exercise revs up that subtle hunger mood
lurking under the surface and then you don’t even know any more how much
you’re overeating. Meals grow bigger while seeming to grow smaller.
Extra snacks sneak in.
Let’s
say you’ve tried all the standard advice – every diet out there. Some
of them might even work for a short time, until you fall off the wagon
and gain back even more than before. After a while you start to doubt
your willpower. If the prevailing medical theory is correct, if weight
is a matter of calorie control, then your problem is a weak character. It’s your own fault. That’s the message beamed across our culture from all directions.
But
the concept of willpower is anathema in psychology. Cognitive control
is much more subtle, complex and limited in its ability than the lay
notion of willpower. That notion is false and harmful to mental health.
What is willpower anyway? It’s pitting long-term rewards against
short-term rewards, and you’re going to fall off that wagon sooner or
later. Every time you fall off, you do more damage than you can undo by
climbing back on again. And even when you think you’re firmly on the
wagon, most of the psychological complexity runs under the surface of
consciousness and therefore you can’t possibly realise how much you’re
sabotaging your own efforts.
Where
does that leave you? At the end of that seemingly inevitable
progression, you’re demoralised and depressed. You can do anything else
you put your mind to but somehow you can’t manage the weight loss. And
so you enter a disastrous spiral. If you’re going to be miserable
anyway, you might as well indulge yourself. The food at least mitigates
the misery. You slip into comfort eating, self-medication and addiction,
and lose all motivation. You fall into the deepest part of the
psychological quagmire and your chance of recovery is small. A recent study showed that if you’re obese, your chance of getting back into the normal range is less than one in 100.
Most
doctors, trainers, and healthcare professionals think about weight from
the perspective of chemistry. It’s calories in versus calories out. Eat
less, exercise more. Different schools of thought posit that all
calories are equivalent, or that fat calories are especially bad, or
that carbohydrate calories are particularly to be avoided. All these
approaches focus on the way that calories are digested and deployed in
the body. They ignore psychology. Most studies treat the psychology of
hunger as an inconvenience. A ‘properly’ controlled study forces
participants to eat a set amount of calories, thus screening out the
annoying influence of autonomous human behaviour. And still, for all
that has been learned from this mainstream medical approach, the advice
is failing us. More than two-thirds of the US population is overweight.
More than one-third is obese.
As
I reviewed the discouraging rise of obesity in the US and all over the
world, and the discouraging shrinking space between my own belly and my
desktop, it seemed to me that the mainstream focus is almost entirely
wrong. The obesity epidemic is not an issue of calories or willpower. I
began to suspect that our problem with obesity is a problem of poisoning
the normal regulatory system. We possess a system that’s intricate and
beautifully calibrated. It evolved over millions of years to be good at
its job. It should work in the background without any conscious effort,
but for more than two-thirds of us it doesn’t. What are we doing to
ourselves to screw up the hunger and satiety system?
For
about a year, I experimented on myself. I used what’s called an
event-related design, which involved some arduous sacrifice (or at least
some boredom). Simply put, I ate the same damn thing every day to
establish a consistent baseline. I measured weight, waistline, and kept
notes on everything I could think of. Then I changed one thing in one
meal and monitored its tiny, perturbing effect over the next several
days. When the measurements went back to baseline, I’d try a new
perturbation. Each tweak by itself gave a small signal, but after a
while I could average across many events and watch the pattern emerge.
Of course I had no illusions of discovering anything new. This wasn’t
formal science. It had a sample size of one. The point was to find out
which of all the conflicting advice flying back and forth out there
resonated with my own personal data. What should I believe?
As
usual, the most instructive part of the experiment turned out to be an
incidental observation. Never mind whether some foods grew or shrank my
poundage. I noticed instead that some acts grew or shrank my level of
hunger. I knew when my hunger mood was up, even if I didn’t consciously
feel hungry, because somehow I’d end up at the lunch deli early. And
after I finished eating, it didn’t seem like I’d had as much food as
usual. Maybe they’d slipped me a smaller sandwich?
When
my hunger mood was down, the roster of priorities would shift and I’d
get caught up in my work. Somehow lunch would get delayed by an hour. My
moment-by-moment decision-making was warped. Each time it happened it
seemed as though there was some other reason for it, but I couldn’t
ignore the pattern accumulating in my notes.
Three
bad habits appeared to consistently boost my hunger. I call them the
super-high death-carb diet, the low-fat craze, and the calorie-counting
trap.
The
super-high death-carb diet has become normal US fare. We get up in the
morning and eat a croissant, or pancakes with syrup, or a muffin. Or
cereal and milk. The cereal is all carbs. Then comes lunch. Suppose I’m
unhealthy and eat a fast-food, McDonald’s lunch. We think of it as
greasy food, but beyond the grease the burger has a bun and the ketchup
is sugar paste. The fries are all carbs. The large soda is sugar water.
The grease is only a tiny part of the meal. Maybe you feel morally
superior and prefer a ‘healthy’ lunch, a deli sandwich that’s mainly
French bread. And chips. And a Snapple. All carbs.
The
afternoon snack is some sugary beverage at Starbucks and a cookie. Or a
power bar, which is a candy bar with spin. If you’re good, maybe a
banana, which is as high carb as you get in the fruit world. Dinner?
Piled with potatoes, pasta, rice, bread. We think we’re healthy eating
sushi but it’s mostly rice. Maybe you go for a nice healthy soup. It’s
thickened with flour and has noodles and potatoes. And every meal comes
with soda, or juice, or ice tea, or some other sweetened drink. Then
dessert. Then a snack before bed. It’s all carbs. You can’t walk through
a supermarket without being assaulted by carbs on all sides. Some
people talk about complex carbs versus refined sugar. They have a point,
but take out the refined sugar and it’s still a staggering amount of
carbohydrates. The super-high death-carb diet has warped our sense of
normal.
The
low-carb people might be right for the wrong reasons. Starting with
Robert Atkins, the American cardiologist who first popularised the diet,
an entire physiological theory has sprung up. In that theory, if you
cut out enough carb, your body switches from using glucose to using
ketones as the main energy-transporting molecule in your blood. By using
ketones, the body begins to draw on its fat reserves. Moreover, by
reducing blood sugar, you reduce insulin, the main hormone that promotes
the deposition of fat in the body. Less carbs, less fat. The theory
sounds good and might have some validity, but its impact on obesity
remains controversial. One recent paper seems to smack it down entirely.
The
study monitored two groups of people. For six days, one group ate
low-carb, the other low-fat. Both were strictly forced to eat the same
number of calories. The result? The low-carb group did not lose more
weight. Actually, the low-fat group did. The low-carb people might have
reduced their insulin, but the theory didn’t really translate into
magical weight loss. Given all that contradiction, what can we say about
the low-carb approach?
Skip
breakfast, cut calories at lunch, eat a small dinner, be constantly
mindful of the calorie count, and you poke the hunger tiger
The
theory and the experiments might be right as far as they go, but they
miss the most important point. They emphasise how calories are deployed
in the body instead of emphasising the motivated state of hunger. It
would be encouraging to see more studies on how different diets affect
hunger regulation. It is now well-established that a high-carbohydrate
diet increases your hunger. A low-carb diet removes that stimulant.
Taking all this together, the evidence suggests that a low-carb diet
doesn’t make you lose weight because of its effect on your energy
utilisation. It makes you lose weight because you eat less. Or (perhaps
more accurately), the ridiculous, super-high death-carb diet stokes up
the hunger mechanism and your eating goes out of control.
Because
that hunger state runs mostly beneath consciousness, it’s easy to
misattribute the result. But in the end, if you follow the death-carb
diet to its conclusion, you can’t help noticing the effect on your
appetite. Extremely obese people reach a point where they’re always
hungry, never full. They can eat six dinners’ worth until their stomachs
feel stretched and terrible, about to split in the middle, but the
brain isn’t satisfied.
The
low-fat craze works the same way. I grew up in the era when public
service commercials on TV warned us about the dangers of fat. Poor data
and a rush to conclusions might have led the medical community to that
recommendation. Don’t eat butter. Don’t eat eggs. Don’t drink whole
milk. Take the skin off chicken. Eat low-fat yogurt (which is still
chock-full of sugar). Dietary fat might have its medical downside; I
don’t think the data are perfectly clear yet. But cutting out the fat
has led to a disaster. As numerous studies have now established, fat
reduces hunger. Take it away and the hunger mood soars. It’s not a
simple relationship, and the effect is gradual. Remember, your
hypothalamus takes in complex data and learns associations over time.
Give it a few months of training with a diet that’s stripped of fat, and
it will ratchet up your sense of hunger.
But
the most insidious attack on the hunger mechanism might be the chronic
diet. The calorie-counting trap. The more you try to micromanage your
automatic hunger control mechanism, the more you mess with its dynamics.
Skip breakfast, cut calories at lunch, eat a small dinner, be
constantly mindful of the calorie count, and you poke the hunger tiger.
All you do is put yourself in the vicious cycle of trying to exert
willpower and failing. That’s when you enter the downward spiral.
All
three of these effects – high carb, low fat, and calorie counting – are
increasingly evident in the scientific literature on diet, and also
showed up in my self-observations. Amazingly, even a small tweak to one
meal on one day had a noticeable effect on my hunger mood.
At
the end of all my self-observations and meditations, the time had come
to put the theory to a test. I tried a simple formula. First, moderately
low-carb. The Atkins and Paleo diet purists would scoff. I reduced my
carbohydrate intake by about 90 per cent and in doing so came nowhere
near a low-carb diet. I wanted to avoid the super-high death-carb diet
that most of us eat most of the time. Second, a little higher fat. I
know some people swear by high fat and snack on entire sticks of butter.
I don’t know what the research is on that kind of thing, but all I
wanted was to avoid the extremity of a diet stripped of fat. Third, I
could eat as much as I like at each meal. That last proposition was the
hardest. When you want to lose weight, it’s hard to wrap your mind
around the concept of eating more. I simply had to trust a bizarre
psychological twist: if I try to eat less, I’ll end up eating more.
I could give a list of foods – salmon, peanut butter, pork chops, apples, tomatoes, chicken with
the skin, tofu, eggs, and on and on – but really the concept is more
revealing than the details. The diet had nothing to do with standard
health advice. It had nothing to do with how those particular foods
chemically affect my body. I wasn’t thinking of my arteries or my liver
or my insulin. The approach was designed to speak to my unconscious
hunger control mechanism, to encourage it to eat less. And it worked at a
slow drip of about two pounds a week, trailing off finally to a much
more comfortable weight. Twenty years of accumulation, 50 extra pounds
(I cringe to admit it) went away in a few months.
There is no effort in an all-I-want diet of moderately fat comfort food. I simply sat back and watched my brainstem do its thing
The
beauty of the method was that it required no effort. By effort, I mean
that dubious concept of willpower. Pitting long-term goals against
short-term rewards. When the hunger mood rises, the personal struggle is
heartbreaking. I know all about that struggle and the weird thing is,
the struggle is alluring. It might be dreadful, and it might be
counterproductive, but it makes you feel like you’re doing something.
Our society is impressed by hard work. Think of those people exercising
maniacally on that TV show The Biggest Loser. We expect
progress to be punishing, and we admire the people who push themselves
to super-human limits. Another psychological trap, I guess. None of that
self-flagellation turned out to be necessary. I had to reconcile myself
to what felt like a lazy method. There is really no effort in an
all-I-want diet full of moderately fat comfort food. I simply sat back
and watched my brainstem do its thing.
I
don’t think I’m alone in this experience. Others have tried a similar
diet, though perhaps for other reasons. Advocating for one particular
weight-loss diet isn’t my point. My message is this: your weight is in
large measure about your psychology. It’s about the hunger mood. Obesity
is a crippling social problem, but to our detriment the research has
almost uniformly ignored this aspect of the situation. Consider this to
be a call to science to focus a great deal more on the psychology of the
hunger mood.
In
some ways, the hunger system is like the breathing system. The brain
has an unconscious mechanism that regulates breathing. Suppose that
system got shut down so that it was up to you to consciously control
your own breath, adjusting its rate and depth depending on factors such
as blood oxygen, carbon dioxide level, physical exertion, and so on.
What would happen? You’d die in about 10 minutes. You’d lose track of
the necessities. The intellectual, conscious mind is not really good at
these matters of regulating the internal environment. It’s better to
leave the job as much as possible to the dedicated systems that evolved
to do it.
What you can do with your conscious mind is to set the general
parameters. Put yourself in a place where your automatic systems can
operate correctly. Don’t put a plastic bag over your head.
Likewise,
don’t eat the super-high death-carb, low-fat diet. Don’t micromanage
your brainstem by counting every calorie. You might be surprised at how
well your health self-regulates.
